Browse Prior Art Database

Compensation of Margin Cursor Movement for Proportional Spacing

IP.com Disclosure Number: IPCOM000037106D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Bowden, JD: AUTHOR [+3]

Abstract

On a display for typewritten characters, there is conventionally a margin scale which is displayed on the screen and is used to indicate the position of the cursor for the generation of the next character to be typed. In non-proportional spacing typewriters, each character has exactly the same width. Thus, the number of characters per inch will be the same irrespective of the type of character; i.e. the number of characters per inch will be the same whether all I's or all W's or some combination thereof is typed. In this case, the movement of what is known as the margin cursor, which is a cursor indicating where along the margin scale typing has progressed, will be exactly synchronized with the location of the character to be printed.

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Compensation of Margin Cursor Movement for Proportional Spacing

On a display for typewritten characters, there is conventionally a margin scale which is displayed on the screen and is used to indicate the position of the cursor for the generation of the next character to be typed. In non-proportional spacing typewriters, each character has exactly the same width. Thus, the number of characters per inch will be the same irrespective of the type of character; i.e. the number of characters per inch will be the same whether all I's or all W's or some combination thereof is typed. In this case, the movement of what is known as the margin cursor, which is a cursor indicating where along the margin scale typing has progressed, will be exactly synchronized with the location of the character to be printed.

However, in the case of proportional spacing of characters, different characters have different widths when they are printed. For example, in certain types of proportional spacing, the letter "i" may take up only three units of spacing, whereas a capital letter "W" may take up seven units of spacing. However, each character spacing which occurs when a character is typed is equal to six units. Thus, each time a character is struck, the margin cursor will move one character space or six units, whereas the printing position of a character along any given line of characters being typed will probably either be greater or less than the number of characters spaced depending on...